Thursday, December 29, 2016

This case was sent by Peter Hammarlund, 2nd year Internal Medicine/Cardiology resident (and self-proclaimed ECG nerd) at Helsingborg Hospital, Sweden. Peter frequently sends me great cases like this, but I never post them because the Swedish standard, explained below, is very difficult to interpret.This time I could not resist.Especially interesting is the troponin data and the manipulated images seen below.Case

Hi Steve,

I was involved in this highly interesting case just the other week.

A previously healthy young man (in his 20s), who smokes two cigarettes a day and has a family history of MI (his father had his first MI in his early 50s), was brought to our ED by ambulance with severe central chest pain without radiation for one hour. The pain was not relieved by Nitroglycerine and only slightly relieved by morphine.

Smith comment: do NOT use morphine until you are either:

1) committed to the cath lab (or other definitive diagnostic modality, such as CT for dissection or PE)

or

2) CERTAIN that the pain is not due to serious pathology.

Case continued

He was tachycardic, but his vitals were otherwise initially normal.

The initial high sensitivity troponin T was 5 ng/L.

(99% reference is 14 ng/L, or less than 15 ng/L; Level of detection is 5 ng/L).

I was working in our CCU when the cardiology consultant (who was sitting right next to me) got a phone call from the ED doctor taking care of the patient. While he presented the case to the consultant we looked at the prehospital ECG (attached as EKG1, time 7.53 am) and the ED ECG (attached as EKG2, time 8.10 am).

At the moment (time 10.45 am) the patient was in the radiology department performing a CT aorta, but right after the CT he developed shortness of breath and only had a saturation of 88% with 15 L/min of O2.

I was immediately very worried about the patient when I saw the ECGs.

What do you say? My answer is below.

Note on technique: These are recorded at the Swedish standard of 50 mm/second. So all intervals appear twice as wide as you are accustomed to! Furthermore, there is only one average complex per lead.

What do you think?

Here is my answer, after a quick glance:

Peter,

Hyperacute T-waves are developing over 17 minutes in V2-V4. LAD occlusion or at least dynamic thrombus.

Steve

As an afterthought just this minute before posting, I compressed the ECGs to 25mm/sec. The difference becomes much more obvious to me:

Peter's Detailed Comment on the ECG interpretation:

The ECG at t = 0 (prehospital ECG) shows sinus rhythm with a minimal ST depression in V3-V4 as well as minimal ST depression in the lateral leads. No significant ST depression is seen in the inferior leads although there is a TWI in lead III that could be non-specific. However, the T wave in V2 looks abnormally large with a hyperacute appearance. Young people might indeed have large T waves in the anterior leads, but the T wave is in fact as large as the whole QRS complex. The positive T wave in V1 could indicate an early sign of anterior ischemia. Although many of these findings may be considered non-specific the appearance is highly unusual in a previously healthy 28 yo man. With a complaint of ongoing chest pain, this is worrisome.

The ECG at t = 17 min (1st ECG in the ED) shows no significant change in V2, but the T wave in V3 is now also hyperacute and the T wave in V4 is also a bit taller. Since the QRS complexes don’t look exactly the same, some of the ST-T changes may be due to different lead placement, but the dynamic change in V3 is too abnormal to ignore. The ST depression in the lateral leads are now gone – could this be pseudonormalisation? There might even be a tiny bit of ST elevation in aVL, and development of slightly downsloping ST segment in the inferior leads (at least aVF and III). Although neither of these ECGs are clearly diagnostic of MI alone, the dynamic changes in combination with a presentation consistent with ACS is highly worrisome.

Smith comment: The ST depression is due to early, and possibly incomplete, LAD occlusion, which is often called "de Winter's T-waves" a type of hyperacute T-wave. 17 minutes later the artery is completely occluded and the ST depression has become ST elevation.

There should NEVER be ANY ST depression in the precordial leads of a young man.

Peter's response:

You are of course spot on. Me and my colleague saw this immediately, and since these ECGs were recorded 2½ hours before the consultant got the phone call we were very worried about the patient.

EKG3 (not shown) was recorded 2.5 hours later(Smith comment: treatment was very delayed!) during the consultation and the diagnosis was now obvious with a huge anterolateral STEMI. The providers had not noticed the ST depression nor the diagnostic T-waves.

Echo hadn't been performed initially, but showed EF 40% and akinesis of the anterior wall. CT of the aorta was of course normal. CT of the lungs showed bilateral infiltrates with gravitational distribution, that initially were interpreted by the radiologist as infectious, but in retrospect were considered to be flash pulmonary edema.

The patient went for coronary angiography that showed an almost complete occlusion in the distal part of LM with a stenosis extending into the proximal part of the LAD.

During PCI the patient needed CPAP and small doses of norepinephrine. He was fully revascularized and was initially admitted to the ICU, but could be moved to the coronary care unit the next day. A formal echo a couple of days later showed EF 50%. The hospitalization was prolonged, due to the development of fever and a small pericardial effusion (postinfarction syndrome?), but otherwise the patient did OK.

This case was up for discussion the next day in our clinic, and I pointed out the subtle, but real dynamic changes, that might have been picked up, not delaying the diagnosis for another 2½ hours.

Many of my colleagues still considered the initial ECGs to be practically normal, although I pointed out that these findings might be considered non-specific if the patient was presenting with e.g. cellulitis in the leg, but highly worrisome in this particular case, since the patient was having ongoing chest pain.

Another thing that made the case a bit more complicated was that the initial hs-Troponin T was only 5 ng/L (positive at < 15 ng/L, level of detection at 5) i.e. not positive, but just above the level of detection. This was when the chest pain had been going on for a little more than one hour.

I think that the ED physician might have been fooled by this. The next troponin measurement in the ICU (6 hours after the onset of chest pain) showed a level of >9998 ng/L.

In retrospect this was indeed a tricky case, but as I pointed out to my colleagues we should learn from it rather than just call it tricky and convince ourselves that it was unavoidable.

Regarding the use of your formula: I believe if you use it on the 2nd ECG it comes out positive with a value of 23.678 (if I measured correctly using 2.5 mm of STE at 60 ms, QTc of 428 and RV4 of 14 mm) clearly indicating subtle STEMI. (A value greater than 23.4 is nearly diagnostic of LAD occlusion in the right circumstances)

Here I have superimposed the ECGs so that you can see the evolution more clearly. The darker lines are the second ECG at time = 17 minutes after the first:

Notice the significant increase in T-wave amplitude in V3 and V4.Notice also the new but subtle ST Elevation in I and aVL, with reciprocal ST depression in lead III.

4) Don't rely on the first troponin, even if high sensitivity (if there is a short time from the onset of chest pain to the blood testing)

//Peter

Comment on the formatting:

In Sweden the different leads usually are presented in the so called Cabrera sequence, which basically means that lead aVR is replaced by -aVR (i.e. aVR with switched polarity, which gives the lead an “up-side-down” appearance) and that the limb leads are presented in a anatomically contiguous order (aVL = -30°; I = 0°; -aVR = 30°; II = 60°; aVF = 90° and III = 120°). This means that the inferior leads are presented next to each other (vertically) and that the high lateral leads (aVL and I) are placed next to each other with -aVR in between. This makes it easier to spot ST-T-changes localized to a specific anatomic area of the heart (at least if you are used to the formatting).

In this case the recordings also have another feature. The tracings that are recorded with a paper speed of 50 mm/s are so called signal-averaged ECGs. There is only one complex presented in each lead, which is an artificially created “mean value” of several ECG complexes. The point of this is to eliminate artifacts.

On the right side (not shown here) we display short rhythm strips at a paper speed of 12,5 mm/s (thereby looking twice as fast as usual if you’re accustomed to a paper speed of 25 mm/s).

Wednesday, December 14, 2016

A middle aged male presented at midnight after 14 hours of constant, severe substernal chest pain, radiating to his throat and to bilateral jaws, and associated with diaphoresis. It was not relieved by anything. The pain was not positional, pleuritic, or reproducible. He had no previous medical history. The blood pressure was 110/60. Physical exam was normal and there was no murmur.

I delved into his reasons for arriving so late after onset, thinking that perhaps the pain had only recently increased, or that it had been intermittent until now, but he confirmed that it was 14 hours of constant pain and it was his significant other who insisted that he go to the ED.

Here was his ED ECG:

I read this as normal--One might say there is ST depression in II, III, and aVF, but this is merely an atrial repolarization wave. --You can see the PR segment sagging down, such that the PQ junction is also depressed. Thus, there is no elevation of the J-point relative to the PQ junction.--ST segment deviation is measured at the J-point, relative to the PQ junction--("Inferior" ST depression would have told us that there is unseen ST elevation in aVL and be a strong clue to high lateral MI)Click here for a couple posts on Atrial Repolarization

He was given an aspirin and a troponin was drawn. If this is MI, then after 14 hours, the troponin should be elevated.

The troponin I returned at 4.1 ng/mL (ULN = 0.030 ng/mL), diagnostic of myocardial injury.

We recorded a posterior ECG:

V4-V6 are moved around to the back and are really V7-V9.The "criteria" for posterior STEMI are 0.5 mm STE in one lead.There is zero ST Elevation.There are tall R-waves in V2, which could be a sign of old or well developed posterior MIHowever, the ECG shows no evidence of acute MI whatsoever.

We gave ticagrelor and heparin and sublingual nitro, with plans to start a nitro drip, but the BP dropped to 80/50 before the drip was started.

The pain was unrelieved.

What do you want to do?

The elevated troponin is diagnostic of myocardial injury. Is it acute or chronic?

There was a normal creatinine and no evidence of heart failure and no other reason for chronic injury, so it must be acute.

Acute myocardial injury:

Is it myocardial infarction, or perhaps myocarditis?
If it is MI, is it type 1 or type 2?
Is it STEMI or NonSTEMI?
Is it acute persistent occlusion?

The patient had no hypertension, no tachycardia, a normal hemoglobin, no drug use, no hypotension/shock, no murmur of aortic stenosis.

The patient had been on a long drive, suggesting possible pulmonary embolism (this was unlikely given absence of tachyardia, hypoxia, or any other feature of PE), so we sent a d dimer. [We also looked at his aortic root by both parasternal and suprasternal views, and the aorta was normal.] The d dimer returned below the level of detection, ruling out PE and making dissection very unlikely.

We could not rule out acute epicardial coronary (large artery) occlusion.

What do you want to do now, considering you will need to awaken the hospital's only catheterization team, which must be alert for the next long day in the cath lab?

I called the cardiologist on call and we agreed that we needed to activated the cath lab.

The patient was found to have an acute 100% occlusion of the circumflex proximal to 2 obtuse marginal branches. It was opened and stented with a door to balloon time of about 120 minutes (this is long for STEMI, but very short for a high risk Non STEMI).

A post cath ECG is shown:

No significant change

The third troponin, drawn before the artery was open, returned at 6.2 ng/mL.
The 4th, after the opening of the artery and release of troponin from the cardiac circulation, was 99.9 ng/mL

So this was a very large MI!!

The formal contrast echo the next morning was difficult technically but showed an inferior wall motion abnormality. It is unclear if this is "inferobasal" which is the new echo term for Posterior.

Learning Point

Acute coronary occlusion may occur with no ECG findings whatsoever. Some NonSTEMI require emergent cath lab activation to save viable myocardium at risk. A patient who has a high clinical suspicion of MI should go to the cath lab. This is not just my opinion, but the opinion of the American College of Cardiology and American Heart Association.

This is from the 2014 ACC/AHA guidelines. Earlier versions are more specific. "A subgroup
of patients with refractory ischemic symptoms or hemodynamic or rhythm instability are candidates for urgent
coronary angiography and revascularization."

Here are the European Guidelines:Timing of invasive strategy: Immediate invasive strategy (less than 2 h) in Very-high-risk NSTE-ACS patients (i.e. with at least one very-high-risk
criterion according to Table 13 (pasted below) have been generally excluded from
RCTs. Owing to a poor short- and long-term prognosis if left untreated,
an immediate (i.e. less than 2 h from hospital admission, analogous to
STEMI management) invasive strategy with intent to perform revascularization
is recommended, irrespective of ECG or biomarker findings.

A patient who presents with chest pain and an otherwise unexplained elevated troponin has acute MI. If the pain is refractory to medical management, no matter what the ECG shows, the patient should go emergently to the cath lab.

It is critical to use this formula only when the differential is subtle LAD occlusion vs. early repol (normal variant ST elevation). There must be ST Elevation of at least 1 mm. If there is LVH, it may not apply. If there are features that make LAD occlusion obvious (inferior or anterior ST depression, convexity, terminal QRS distortion, Q-waves), then the equation MAY NOT apply. These kinds of cases were excluded from the study as obvious anterior STEMI.

If you use these values:
Computerized QTc = 431 ms
ST elevation at 60 ms after the J-point in lead V3 (STE60V3) = 1.5 mm
R-wave amplitude in V4 (RAV4) = 6.5 mm

The resulting value = 25.1. Any value greater than 23.4 is very likely to be LAD occlusion.

Case continued

This was recorded 22 minutes later: Again, nonspecific ST-T abnormalities

What do you see here?The computer still reads "nonspecific ST-T abnormalities"Note the computer reads the ST segment:For V2, it is 1.03 mmFor V3, it is 1.58 mm"Normal" for a male over age 40 is up to 2.0 mm in V2 and V3.

Now there is straightening of the ST segment in V2. A straight ST segment is very rare in normal variant ST elevation, and the change makes it diagnostic of LAD occlusion. Inferior ST segments have also evolved. aVL has suspicious coving; it is probably a proximal LAD occlusion.

The ST elevation "criteria" are incorrect.

The patient arrived in the ED and had this ECG recorded at 25 minutes after the 2nd ECG (t = 47 minutes)

So this is the first ED ECG:

The computer interpretation: "Possible old inferior myocardial infarction."Very similar, but now with more ST depression in inferior leads and subtle ST elevation in aVL.Again, diagnostic of LAD occlusion, with evolution of findings.

The cath lab was activated.

This ECG was recorded 26 minutes later, just before the patient was transported to the cath lab:

Very interesting:1. The ST depression in the inferior leads is gone, as is the STE in aVL, suggestive of reperfusion of the high lateral wall.2. There is T-wave inversion in aVL, also suggestive of reperfusion.3. V3 has developed terminal QRS distortion (loss of S-wave), suggestive of evolution of injury to the anterior wall.4. There are the beginnings of Q-waves in V2-V4Thus, it appears as if there has been worsening of the anterior wall and reperfusion of the high lateral wall.

My interpretation when I saw this was that the LAD thrombosis was at the ostium of the first diagonal (D1) and that it had partly reperfused, leaving D1 open and the LAD still occluded.

A 100% proximal LAD occlusion was found, with left-to-left collaterals (from the circumflex) perfusing the 1st diagonal. This explains the reperfusion of the high lateral wall.

Here is the next day ECG:

Reperfusion T-waves in I and aVL, and V2. Some persistent, minimal, ST elevation.

This was the doctor's (my ex-resident's) response:"He now has ST elevations in a different distribution. Was inferior before, now lateral What the heck? I had been considering coronary vasospasm, but the changing distribution seems to make that less likely."

He thought it might be vasospasm of two different coronary arteries.

ECG 7. At 0428 the burning persisted and this was recorded:

Now they are inferior again!!

7 minutes later the burning was gone and this ECG was recorded at 0435:

All STE has resolved again.

The Cath Lab was activated. Here is the last ECG before he left for the cath lab at 0449:

There are now inferior reperfusion T-waves (inferior Wellens' waves!)This supports some degree of infarction.The troponin will be elevated, but not by much as these occlusions were brief.

Outcome

The cath did not show an occlusion or a definite culprit, but some diffuse non-occlusive disease. No PCI was performed.

I do not have the subsequent troponin.

Subsequent Echo was showed LVH and evidence of hypertrophic cardiomyopathy, without a wall motion abnormality. EF was 65%.

The caregivers (emergency physician and cardiologists) were perplexed about what happened.

What happened?

Why the change in location of ST Elevation??? (There are two explanations below)

In 4. and 7., which have inferior ST elevation, the QRS is positive in II, III, and aVF, but negative in aVL (5. also has this QRS axis)

In 6. which has lateral ST elevation, the QRS is negative in lead III, isoelectric in aVF and positive in aVL.

Thus, the limb lead placement was inadvertantly reversed between ECG 5. and 6. And it was inadvertantly reversed back for ECG 7.

So this was a transient inferior STEMI.

Haim KatalanexplanationI
looked carefully at ECG 6-7 and the first ECG with inferior STE. I don't
think limb leads was misplaced. i) the chest leads looks different in ECG 6 from 7. That can not be accounted for by limb lead swap. ii) Also in
ECG 6 the STE in I & aVL have an action
potential shape completely different from the STD in ECG 7 . iii)
also no P wave axis change as would expected in lead swap. So my
impression is that it was multi vessel spasm.

Transient STEMI is usually due to brief thrombotic occlusion that then lyses. This occlusion happened several times. The first time it did not result in chest pain but did result in complete heart block. In Acute Coronary Syndrome, a thrombotic event, a culprit is not always found. And the coronary disease may be mild in such cases: the thrombosis just happens at a minimally stenotic, but vulnerable lesion. It is even possible to have thrombosis with a completely normal angiogram, though in less than 1% of cases. In such cases, all the the atherosclerosis is outside the lumen, in the wall of the vessel. So you cannot see it on an angiogram, which is a "lumenogram." You can see this with intravascular ultrasound, which very well images the thickness of the vessel wall.

Of course vasospasm is usually blamed for these transient ST elevation events, but unseen thrombosis is more common.

The good news is that transient STEMI has a better prognosis than non-transient STEMI, AND ACS with a non-obstructive angiogram has a better prognosis than those with tight stenoses or large thrombus burden.

Learning Points:

1. Always check lead placement when things do not seem right!
2. Beware of Transient STEMI
3. Beware that ACS may have minimal findings on angiogram.

"This ECG was recorded on an asymptomatic 50 year old marathon runner who presented for pre-participation screening."

(This ECG could easily be seen in an ED chest pain patient, and I have seen many)

What do you think?

DescriptionSinus bradycardia.There is high voltage.There is ST elevation in V2 and V3There are inverted T-waves in V2 and V3There are prominent U-waves in V2 and V3Many responders were worried about ischemia or hypertrophic cardiomyopathy.Here was Massimo's response:"I'm very sure of Early Repolarization (ERP) diagnosis in this case. First because I have a good eye on ECGs of endurance athletesSecond because I see a lot of these tracingsThird because the stress test determines the disappearance of ECG abnormalities found at restFourth because the echocardiogram is normalFifth and last, the clinical presentation speaks clearly." Comment

I (Smith) have seen many similar ECGs in ED chest pain patients. I have always believed them to be benign for the reasons described below. But I have never had any data to support my beliefs, so I've never posted them.

Notice also that the QTc is very short. First, one must realize that the last wave is a U-wave, which is common in ERP. So the QT must not be measured in V2 or V3. The QT as measured in other leads is about 420 ms, with a preceding RR of 1500ms, resulting in a Bazett corrected QT interval of 345 ms. This short QT at least makes ischemia all but impossible. ERP is, of course, associated with an increased long term risk of sudden death, but only marginally and only if in inferior or lateral locations:

http://www.nejm.org/doi/full/10.1056/NEJMoa071968#t=abstractIn addition, many readers of this Facebook post were worried about ischemia, including Wellen's syndrome ("What if this patient had presented with chest pain?"): Even in the setting of ischemia, the ischemia would not be represented by this ECG. This is a classic pattern and the QT is so short as to make ischemia very unlikely. This is a normal variant. I have seen this innumerable times in chest pain patients in the Emergency Department. At first glance, it may appear to be similar to ischemic T-waves, but it is not. The large upright U-wave, this high voltage, and the short QT interval differentiate it from ischemia. It is important to remember that even a patient with a normal variant could have a myocardial infarction, just as patients with completely normal ECGs may have MI. It is only to say that the ischemia is not represented on this ECG.See this post on Benign T-wave Inversion.Here is a relevant post on the inverted T-waves of Persistent Juvenile T-wave Pattern with many other the normal variants of T-wave inversion.

However, meeting LVH criteria is not critical, as they are not sensitive.Many cases of LVH show themselves only by the typical repolarization abnormalities. In this case, we see somewhat typical repolarization abnormalities in leads III and aVF.

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Disclaimer

Cases come from all over the world. Patient identifiers have been redacted or patient consent has been obtained. The contents of this site have not been reviewed nor approved by Hennepin County Medical Center and any views or opinions expressed herein do not necessarily reflect the views or opinions of Hennepin County Medical Center.